Adjustable cam actuated hold-down clamp



May 26, 1953 w. B. HERBERT ADJUSTABLE CAM ACTUATED HOLD-DOWN CLAMP 2Sheets-Sheet 1 Filed March 7, 195

m J 7 MJ 4 7 1 f a m Z a w k AP z MM ATTORNEYSr May 26, 1953 I w,HERBERT 2,639,744

ADJUSTABLE CAM ACTUATED HOLD-DOWN CLAMP Filed March 7, 1951 2Sheets-Sheet 2 INVENTOR He rZ'arZ' LBY ATTORNEY5 Patented May 26, 1953UNITED STATE PATENT OFFICE William B. Herbert, Ridgewood, N. J. i

Application March 7, 1951, Serial No.-214,395

Thisinvention relates to jig nuts and is an improvement over theconstruction embodied in my prior Patent 2,464,133, issued March 8,1949, for Jig Nuts.

An object of this invention is to provide a jig nut constructionembodying a pressure or clamping body with adjustable means whereby theclamping body may be placed under suitable clamping pressure to hold awork piece on a table or other suitable surface.

Another object of this invention is to provide a device of this kindwhich is so constructed and arranged that the degree of pressure to beapplied to the work may be closely adjusted so that the same clampingpressure may be applied to similar work pieces as where mass productionis being performed.

A further object of this invention is to provide a device of this kindwhich is simple in construction and canbe applied to machine tool bedsor other surfaces without changing the construction of the tool bed orsurface.

A further object of this invention is to provide a device of this kindwherein the clamping body is formed with a socket or recess within whicha pressure regulating washer engages, the socket holding the washeragainst shifting action caused by application of pressure to the work.

With the above and other objects in view, my invention consists in thearrangement, combination and details of construction disclosed in thedrawings and specification, and then more particularly pointed out inthe appended claims.

In the drawings,

Figure 1 is a detailed side elevation, partly broken away and insection, of a jig nut constructed according to an embodiment of thisinvention, showing the device in released position,

Figure 2 is a fragmentary sectional view taken on the line 22 of Figure1,

Figure 3 is a fragmentary sectional view taken on the line 33 of Figure2,

Figure 4 is a fragmentary sectiona1 view taken on the line 4-4 of Figure1,

Figure 5 is a fragmentary sectional view taken on the line 5-5 of eitherFigure 1 or Figure 4,

Figure 6 is a fragmentary sectional view taken on the line 6-6 of Figure4,

Figure 7 is a fragmentary sectional view similar to Figure 3, butshowing the device in clamping or operative position,

Figure 8 is a fragmentary sectional view of a modified form of thisinvention.

Referring to the drawings, the numeral I0 designates generally a machinetool bed which 2 Claiins.- (01. 144-290) has mounted on the upper sidethereof a Work piece I I. .The bed I0 in the present instance is formedwith an inverted T.-shaped slot I3. The slotI 3 has disposed thereinaheadedupstan-ding bolt I2, and a second bolt I4 is threaded into the bedor table IO'and is provided withan upper head'I5,

A clamping body lii engages on the upper end of the bolt I5 and bearsat. the opposite end against the upper side of the work piece II. Theclamping body I6 is formed with an opening I! through which the bolt I2loosely engages, and a nut I8 is threaded on the bolt I2 and provides ameans for initially exerting clamping pressure on the clamping body I6.V t

The upper side'of the body I6 is formed with a recess 0r socket I9within which a washer 20 is adapted to loosely engage. A pair of camstuds 2| are rotatablymounted in openings 22 formed in the body I6, andthe studs 2| are disposed in alignment and are's'ecured to a lever 23.openings 22 communicate with the socket I9 and each cam stud 2| isformed with a fiat side 24 which is adapted to be disposed flush withthe bottom of the socket I9 when the studs 2| are in released position.

In order to provide a means whereby the washer 20 may be adjusted Withinthe socket I9 so that a selected clamping pressure may be applied to theclamping body I6, I have provided a pair of washer adjusting pins 25which are disposed in sockets 26 formed in the body It and communicatewith the socket I9. The pins 25 are constantly urged upwardly by meansof springs 21, and the pins 25 are locked in adjusted position by meansof set screws 28 which are threaded into the body I6. When the maximumclamping pressure is to be applied to the body It, the upper ends of thepins 25 will be disposed flush with the bottom of the socket I9. InFigure 5 the pins 25 are disclosed in upwardly adjusted position so asto thereby hold the ring 20 above the bottom of the socket I9.

Referring now to Figure 8, the Washer or ring 20a is adjusted within thesocket I9a by means of one or more set screws 29 which are threadedvertically through the clamping bar I6.

In the use and operation of this device the headed bolt I2 is insertedin the T-slot I3 and the outer end of the body I6 is engaged on thefulcrum bolt I5. The inner end of the body I6 engages the upper side ofthe work piece II and the nut I8 is threaded downwardly on the bolt I2.The initial adjustment of the nut I8 may be made by the hand of theoperator and at this The time the lever 23 will be disposed in avertical released position so that the flat sides 24 of the cam members2| will be flush with the bottom of the socket [9. After initial handadjustment of the nut l8, lever 23 may then be swung downwardly to asubstantially horizontal position, thereby increasing the clampingpressure on body I6. In the event it is desired to place the work underless than maximum clampingypressure, the Washer orring lii imay-lberaised upwardly in the socket l9 by loosening the set screws 28 so thatthe spring-pressed pins 25 may move upwardly for the desired distance.When the Pin 25 project upwardly into the socket 19, "the cam studs ormembers 2| will apply a pressure to the body [6 which is less than themaximumnclampr ing pressure.

I do not mean to confine myself to th-eexact details of constructionherein disclosed -but claim all variations falling within the purview ofthe appended claims.

What I claim is:

1. A work c'lampingmeans comprising a, tool bed having a T-slotthereinla clamping body for engaging a workpiece on said tool fbed,'said.b.ody having a vertical bore .between'the ends thereof saidboreterminating "in an enlarged socket opening in the uppersurface of said.clampingbody, an upright bolt looselylengaging through said bore, aheadon said bolt ,len-gaged in saidT-slot, a nut threaded on said bo'lt'foradjusting said clamping body relative to said workpiece, a washerinterposed between said nut and said bodyfand locatedwithin-each socket,a pair of aligned substantially cylindrical scam members rotatablycarried :by said-body and le ctending inwardly into saidbore just belowthe ,bottommf d 9k 3 am fill lb l' ha g a-fla ifl adapted to be disposeduppermostand con'frontins sa Washer whe said an em e s. ar i released.position, a lever-fixed to saidcam meme bers, and spring biased pinmeans carried by said body for adjusting said washer relative to saidcam members.

2. A work clamping means comprising a tool bed having a T-slot therein aclamping body for engaging a. work piece on said tool bed, said bodyhaving a vertical bore between the ends thereof, said bore terminatingin an enlarged socket opening I in the aupper 'surfacegofgsaid clampingbody,

an upright boltfllooselyeengaging through said bore, a head on said boltengaged in said T-slot,

-;-a,.nut threaded on said bolt for adjusting said clamping bodyrelative to said workpiece, a washer interposed between said nut andsaid body and located within each socket, a pair of alignedsubstantially cylindrical cam members rotatably carried by said body andextending inwardly into said bore just below the bottom of said socket,each cam member having a flat face adapted to be disposed uppermost andconfrontingsaid washer whensaid cam'membersare i n released ,position, a'lever fixed lto saidscam members, atleast one spring pressed washer 3d? justing pin slidably carried'by said bodyfinconfronting position withrespect to said washer, and threaded locking means carried by saidbodyfor locking said pin in adjusted position.

WILLIAM B. vI-IERIBER'I'.

